The present invention relates to an apparatus for delivering coolant to a rotary machine tool and in particular to an apparatus that directs the coolant to the machine tool first for cleaning the tool afterwhich the coolant is sprayed upon the workpiece to cool and lubricate the workpiece and machine tool.
While performing a material removal operation, grinding for example, it is necessary to provide a coolant to both cool and lubricate the workpiece and the cutting tool. Typically, oil or water based cooling fluids are used for this purpose. The coolant is often supplied to a manifold adjacent to or surrounding the cutting tool which distributes the coolant to one or more outlets from which the coolant is discharged onto the workpiece. With respect to a grinding operation, a coolant flow rate of approximately 30 gallons per minute with a coolant pressure of 30 psi has been used generally satisfactorily to cool the grinding wheel and workpiece. However, during a machining operation, particles of material being removed from the workpiece can accumulate in the cutting tool. This is particularly true with grinding where an abrasive work surface is used to remove very fine particles of material from the workpiece. The particles accumulate in the abrasive work surface, reducing the ability of the abrasive to remove material. This accumulation is typically referred to as a "load". When a significant load has been accumulated, grinding performance is decreased and eventually the grinding wheel must be replaced.
Accordingly, it is an object of the present invention to provide an apparatus for cleaning the load from a machine tool such as a grinding wheel to thereby extend the useful life of the tool.
It is a feature of the present invention to provide a housing closely surrounding the machine tool with a portion of the tool extending from the housing to engage the workpiece. The housing is provided with one or more small outlet orifices through which a coolant spray is projected at a high pressure against the work surface of the tool. The impact of the coolant spray against the tool removes the load from the work surface thereby cleaning the tool. The housing is contoured to the tool and closely spaced therefrom to provide minimal clearance for drainage of the coolant. The coolant is thus forced to remain in close contact with the rotating tool and is then forced by the rotating tool and housing against the workpiece where the coolant serves to cool and lubricate the workpiece.
It is an advantage of the present invention that cooling is improved enabling the coolant flow rate to be reduced.
It is a further advantage of the present invention that the rate of metal removal can be increased while the life of the work tool is also increased.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in conjunction with the accompanying drawings.